Oviposition preference and olfactory response of Diaphania indica (Lepidoptera: Pyralidae) to volatiles of uninfested and infested cucurbitaceous host plants

Abstract

The cucumber moth, Diaphania indica (Saunders) (Lepidoptera: Pyralidae), is a major pest of cucurbitaceous plants. The oviposition preference and olfactory response of larvae, mated and unmated male and female adults to volatiles emanating from uninfested and infested plants of four species of cucurbitaceous host plants and odours of conspecifi cs were recorded. Also the role of experience in the host fi nding behaviour of D. indica was evaluated. The experiments were done using a wind tunnel, olfactometer attraction assays and oviposition bioassays. The results reveal that fewer eggs were laid on infested plants than on uninfested plants. Females signifi cantly preferred cucumber over squash, melon and watermelon. Cucurbitaceous plants elicited adults of D. indica to fl y upwind followed by landing on the plants. The effect of experience on the olfactory preference of D. indica was dependent on the host plant. Females that had experience of cucumber, squash and melon plants were signifi cantly attracted to the same plant, but not in the case of watermelon. Larvae of this pest were attracted only to volatiles of uninfested cucumber, squash and melon, whereas volatiles of conspecifi cs, infested plants and intact watermelon did not attract larvae. This study is an initial attempt to investigate the role of volatile infochemicals in the host-fi nding behaviour of D. indica. These results provide baseline information for the development of new control strategies against D. indica.